Fluid actuated regulator



Patented July 8, 1952 PATENT oFFiic'E FLUID AGTUATED REGULATOR Arthur R. Worsten; fainted Post, N, assi iior to Iiig'ersou and com any, New York, N. Y,, a corporation or N'etv Jersey Application i Jecember 18, 1948 Serial No; 66,651

This invention relates to regulators andmore particularly to regulators which are adaptedto pressure operated control devices for adjustin theoutput pressure of a compressor, or similar machine, in accordance with the load demand thereon. h I d i As; is well known to those familiar with the art, the receiver-pressure for a eompressorwill vary in accordance with the vdemand unless the output of the compressor'is variedin' accordance with this demand. There are, of course, varioustypes of control devices which act to maintain a constant output from the compressor by opening and closing clearance or by-pass valves for thecompressor in, accordance with the demand However, many of these devices are extremely complicated instructure and function and-are, accordingly, expensive toconstruct and often require considerable attention in their maintenance. Also, some'of these devices, clue to their'operatin'g characteristics, act immediately upon any change in demand to actuate s'aid valves an efiort to maintain a constant output pressure.

leads to erraticoperation of the compressor under conditions wherein the fluctuations indemand are cit-short duration i Y v c It is, accordingly, one object of this invention to control theoutput are are of the compressor in; accordance with demand ehaiigeg of piecetermined' duration.- v

A further object of this "Ventioh lsto' provide aregulator Which is simple rugged in (36h struction. v

' Qther objects will become obvious from the following s ecification acin p flying di'EW- i'n'gshowing a vertical elevation, partly section, of a regulator constructed in accordance with the practice of the invention and adapted to a conventional control element: I

Referring to the drawing, a preferred form of the regulator isshown which comprises, general, a body defining a reset chamber H, a pressure chamber l2 and a coiitrolchambei 13-, the latter chamber beingexposed to a cofiven= tional control means M which acts res'por sivelv' to changes in the yams of pressure within-the control chamber l-3 tocoiitrol the output of the compressor (n t shown) or c'itliei machine to which the regulating" device is adapted.

r The value or the fluid pressure the chamber 13 is' dependent, general, on the pressure the ber is regulated by the size of an outlet, such as the fixed orifice or bleed l5, communicating the chamberl3 with the atmosphere. I

It is to be noted that this arrangement of the chambers l2 and I3 and associated fluid passages provides a pressure amplifier in: that a slight change in pressure in the chamber {[2 will cause the valve mechanism H- to vary,- further, the rate of flow of fluid into the chamber i3 thereby causing arelatively large change inpressure in the latter chamber.- Under circumstances wherein the initial change in pressure inthe chamber [2 does not result a change inpressure in the control chamber i3 sufii'cient to effect the operation of the control means 14 to return the pressurei-n the chamber 12 to the predetermmed de= sired pressure value, the resultant pressure diffe'rential which exists-between the reset chamber H and the control chamber I3 causesf'a further change in the setting of the valve H. In fur= therance to this end, a means is provided tovary the pressure in the reset chamber in response to variations in pressure in the control chamber.

To accomplish this function 115i the illus'tiated chamber l2, communicated by'aconduit' fzuwith form of the invention, the" chamber III is com:- municatecl with the chamber l3 by aoas'sage l6, through which the rate of now or fluid i con:

trolled by a valve, designated in general 153 [8.-

Briefly, then, with the arrangement described. changes of pressure in the chamber [2 are smell: fied' in the chamoer" i3" thereto rendei'in'g the c changes or pressure in the chamber l e to vary the out i t'oflaoompressor (noi showm or r machine-town nit s connected. If this inpressure sustained for a predeter p'ei iod'oi time, determined by the setting of the v lve is, theoieedingi action that occurs between the reset chamber n and the chamber to win ause further changes ili'ti i' setting of the vaiiie 1 t'o'efiect thereturii of the output eressui-e of the compressor (not shown) to the redetermined desired valiie in a manner ex lained in greater detail-hereinafter;

Considering the structure ai id fiincti oi the regulator in greater detail', the body IO -of the reg lato is made u of c ntral section 1' 9 and eiid sections 20 and" 21. The central section is defines the chamber I I, and is shown as being of generally tubular shape with openings I22 and ate the valve I1, the opening I22 is formed with a somewhat smaller diameter than the opening =I23 so that the diaphragms 22 and 23 have unequal surface areas exposed to fluid pressure within the reset chamber l'I A tubular j'memberf 24 extends between and is clamped at its opposite ends to the diaphragms 22 and 23 by flanged bolts 25. The diaphragm, in this instance-having the said larger surface area is 23, so that pressure fluid in the chamber ,II exerts a downwardly directed net force on the diaphragm 23. The opposite side of. this diaphragm'23 is exposed to i'luid pressure within the pressure chamber I2 defined by arecess 26' in the section 2!. Thus, the diaphragm 23 moves in response to changes th'e'pressure difierential which exists between the reset chamber and the pressure chamber I2;[any increase in pressure in chamber I2 or decrease inpressure in chamber II results in movement of 'th'ediaphragm 23 in the upward direction, a converse change of these pressures results, of course, -in-movement of the diaphragm in the opposite; or downward, direction.

- The reciprocative motion of the diaphragm 23 'is -utilized to control the flow of fluid from the pressure chamber I2 to the control chamber I3 and, accordingly, thevalve I1 is arranged to be actuated by such movement. To this end, the valve-l1 comprises a valve housing 28, threaded in an'opening 29 between the chambers I2 and I3, in which is mounted a spring pressed needle valve 30, the tapered end of which extends through an orifice 3I in the housing 28 into contact with a head 21 on the 'bolt clamped to the diaphragm 23. 'In the embodiment as shown, the needle valve 30 tapersinthe direction of the head 21 so that the flow area through the orifice 3| increases as the valve.30 is forced into the housing against the pressure of the spring 32 biased between an abutment I32 on the valve 30 and a mounting or guide plate disposed in the hous-.

ing; 28 and having a central hole I33 through which the valve 30 slidably extends.

' Disposed on theside of the section 2I opposite to; the recess 26 isthe control chamber I3, the open end of which is enclosed by a plate I34 of the control'means I4. The control means I4 may be-of any conventional type control device which is actuated in response to changes in fluid pres, sure, For the sake of illustration, the control means shown comprises a plurality of control elements 33, the ends of which have unequal cross sectional areas exposed to thepressurewithin the 'chamber'and which are, accordingly, actuated at various predetermined values of pressure within the chamber I3. In order to prevent the leakage of fluid from the .control chamber I3 along the elements 33, a blanket or diaphragm 34 is placed over the ends of the elements 33 extending into the chamber I3 "and its marginal portion is clamped between the section 2| and the plate I34, thereby obviating the need for a tight fit between the elements 33 and the plate I 34 in which they are slidably mounted.

Fluid, however, is allowed to escape from the chamber I3 at a predetermined rate through the 4 valve I8 and the orifice I5 in a plug 35 threaded in a passage 36 communicating the chamber I3 with a constant pressure source such as the atmosphere. The valve mechanism I8 is, in construction, similar to the valve mechanism I1 with the exception that the needle valve 31 of the valve I8 is mounted loosely in its guide 38 in orderuto providea flow path for fluid passing through the valve; whereas-inathe'valve I1 holes 39 are provided in the mounting plate 40 for passage of fluid through this valve I 1.

Adjustment of the needle valve 31 to regulate the flow area through the orifice 4|, in a plate :42, through which the needle valve 31 extends. is accomplished by means of a plug 43 threaded ina branch of the passage I5 and bearing against the tapered end of the needle valve 31. In this instance, as was in the case of the valve I1, movement ofv the needle valve 31 into its housing 44, journaled in the passage I 6, against the pressure of the spring 45, tends'to increase the fiow area through the orifice 4|. Such downward movement is accomplished byright hand rotation of theplug43.

With this arrangement, the pressure differentialwhich exists between the control chamber I3 and the pressure chamber I2 is dependent on the difierence in flow areas between the orifice I5 and the orifice-3 I; and the delayed action of the valve 30 in response to changes in pressure in the chamber I I resulting from a. differential in pressure between the chamber II and the chamber I3, is dependent on the flow area of the orifice 4I-. For example, assuming the pressure in the chamber I2 increases, the flow area through the orifice 3I is decreased by the action of the valve :30 in response to this pressure increasaand the pressure in the chamber I3 is decreased accordingly. This decrease in pressure in the chamber =I3 causes a pressure differential to exist.- between the chambers. II and I3 and pressure fluid will fiowiromthe chamber I.I.to the chamber I3 'at a rate determined by the size of the flow area of the orifice M and the magnitude of the said pressure diflerential. Thus; the smaller the flow area through the orifice-4|, the slower will be the bleeding action for a given pressure differential between the chambers I I and I3. The slower this action is, the slower the, action of the valve 30 will be, and accordingly, the longer will be the delay in the action of the elements 33 in response to this decrease in pressure in the chamber II. Of course, these pressures will not equalize unless the pressure in the chamber I2 is at the desired value, i. e., the actionofthe valve 30 will increase the pressure in the chamber I 3 in accordance with thedecrease in pressure in the resetchamber II. r

In order to overcome, the force of pressure fluid in the chamber I2acting against the diaphragm 23, at any given pressure, and also to allow movement of the diaphragm 23, a spring 48 is mounted within the section 20 and biased between the bolt 25 clamped to;the diaphragm 22, and an adjusting screw 41 threaded in the outer or free end of the section 20. Thus, the compression of the spring 46 may be adjusted by the screw 41 in accordance with the pressure differential between the chambers II and I2 to obtain a predetermined setting of the valve 30.

In the following description of the operation of the regulator, it will be, assumed, for the sake of example, that the chamber I2is communicated with the. discharge side of a compressor (not shown) and that it 'isdesired to. maintain a disch'ar'gepressure.otfIOI) pfs. i. It willjals'o be 5.. assumedthat at 100p. s. i. pressure in the; cham: 61212; .the .difierenceinflow area between. the orifice I15. and the orifice .3}? will .be suchas tqmaintain acontrol pressure of; 50. p .s. .i. This meanaofcourse, that the pressure in, the reset chamber is also.50 p. s, i.. Now, in the. event the load on. themachine decreasesto apoint where the pressurein the chamber I 2 risesto. 102 p. s. i., thediaphragm 23 will, accordingly move upwardly ,thereby pausing the; needle valve .39, under the action of the spring. 32,1110 be moved furtherpinto. the orifice 3I.to; decrease the flow area. therethrough. This results ina decrease in pressure in thecontrol chamber;.l3 to, say, .40 p. s. i., thereby. causing ,movementofone of the control elements 33 to reduce the output of said compressor, sayto', three-quarters otitsfull output. ,ie pressure in the reset chamber I l, howeven remainstemporarily at,5 p s. i.,due to the fine restriction at the orifice. 4|. If the,load .de-

. mand remains atthree-quarters of-full; capacity of the machine and the pressure in the chamber remains at 1.02 pounds for any. .length of time, the slowbleedingaction from the chamber I l..,t.o the chamber I3 due to the lopoundgdifierential. therebetween, will lower the, pressure; in the. chamber I I causing thediaphragm 23. to move upwardly to close; vfurther, the valve 39 an amount justsufiicient tomaintain the 10 pound pressure differential between the chambers II of flow into the chamber I3 increased-thepressure therein to a value equal tothat in the reset chamber I 5 thereby halting the reset action. In this particular example, if the demand had been three-quarters of the total output of the com-.

pressor, the stable pressures at this output in the chambers I I and I3 would, of course, have been 40p.s,i-.

In the event that demand increases, the reverse action occurs in which-the diaphragm 23 moves. the valve to to increase the flow area through-the orifice, 3| therebyincreasing the pressure in the chamber I3 and the elements 33 are, actuated to increase the output of said compressor; The pressure differential betweenthe.

chambersv II and. I3 is,of course, reversed and the bleeding action occurs from the chamber I3 to the chamberl Ii.

It is now obvious .from the previous discussion that a regulating device constructed in-accordance with the practice of the invention accomplishes, among others, the objects hereinbefore stated, and provides a simple and durable regu-' lating device capable of effective operation throughout the entire load range of the compressor or other machine to which it may be adapted. Also, the reset feature in response to a sustained load change will cause the control device to regulate the output-of the machine to match the demand at a desired pressure and, further, will lead to stability of operation over periods of sudden load changes or demands.

While I have shown and described a specific form of.my invention, it .to be understood that various changes .andmodificationsmay. be made without departing from the spirit of the inventionas set .forth in .theappended claims. Iclaimz'. y

. 1. A regulator comprising a body having a reset chambeua pressure chamber .and a control 'cham-ber'therein, an inlet for constantly communicating the pressure chamber with a source pressure changes in the control chamber for controlling the machine-to be regulated,=means for communicating the reset'chamber'with the control chamber, an outlet for the-continuous escape of pressure fluid from the control chamber, means for-communicating the pressure chamber with the control chamber, and a valve acting in response to changes in pressure differential between said reset chamber and said pressure chamber forcontrolling the flow of pressure'fluid into the control chamber.

2. A regulator comprising a body having a reset chamber, a pressure chamber and a control chamber therein, an inlet for constantly communicating the pressure chamber with a source of pressurecontrol means responsive to pressure changes in" the control chamber for controlling ber to permit the flow of fluid between the reset and control chambers whenever there is a pressure differential therebetween, means for communicating'the pressure chamber with the reset chamber, a valve acting responsively to changes in pressure differential between the reset chamber and the pressure chamber for controlling the flow of pressure fluid into the control chamber, and an atmospheric bleed for the control. chain ber; i 3. A regulator comprising a body having a reset chamber, a pressure chamber and a control chamber therein, an inlet for constantly communicating the pressure chamber with a source of fluid pressure, control means responsive to pressure changes in the control chamber for controlling the machine to be regulated, an inlet for communicating the pressure chamber with the control chamber, an outlet for the control chamber to permit the constant flow of air from the control chamber, a valve for controlling the flow of pressure fluid through said inlet, means acting' responsively to a pressure differential between the reset chamber and the pressure chamber to actuate said valve for controlling the flow of pressure fluid into said control chamber, means for communicating the control and reset chambers, and valve means for controlling the flow of pressure fluid between the control chamber and the reset chamber.

4. A'regulator comprising a body having a reset chamber, a pressure chamber and a control chamber therein, a pressure fluid inlet for the pressure chamber, control means responsive to pressure changes in the control chamber for controlling the machine to be regulated, means for communicating the pressure chamber with the control chamber, a valve in the second said means for controlling the. flow of pressure fluid between the pressure chamber and the control chamber, reciprocative means between the .reset chamber and the pressure chamber acting vresponsively to changes in pressure differential therebetween for actuating said" valve, an orifice for the control chamber to permit the escape of pressure fluid therefrom, means for communicating the 1 control and reset chambers, and. a means for controlling .the:flow of pressureifluid through the last saidsme'ans; l; y o

5. A regulator comprising'a body having a reset chamber, a pressure chamber and a control chamber therein, a pressure fluid inlet for the pressure chamber, control means responsive to pressure changes in the control chamber for controlling the machineto be regulated, diaphragms at the opposite ends of the reset chamber having unequal areas exposed to the said chamber, an atmospheric bleed for the control chamber, means for communicating the pressure and control chambers, a -valve actuated by one of said diaphragms for. controlling the flow of pressure fluid between the pressure chamber and the controlchamber,- means for connecting said diaphragms, meansfor communicating the control and reset chamber, and means for controlling the flow of pressure fluid between the control chamber and the reset chamber.

6. A regulator comprising a body having a reset'chamber, a control chamber and a pressure chamber therein, an inlet for constantly com municating the pressure chamber with a source of pressure fluid, means for communicating the pressure and control chambers, a valve for controlling the flow or pressure fluid through said means, diaphragms enclosing the opposite ends of the reset chamber having unequal areas of surface exposed to said reset chamber, a member connected betweensaid diaphragms for transmitting movement therebetween one of said diaphragms being positioned between the reset chamber and the pressure chamber and acting responsively to the pressure difierential therebetween to actuate said valve, an outlet for the control chamber, means for communicating the reset and control chambers, and means for controlling the flow of pressure fluid through the last said means.

7. 'A regulator having a pressurechamber .in constant communication with the source of fluid under pressure, a control chamber in communication with a 'means actuated in responseto variations in pressure in the control chamber to control the device to be regulated, a passage communicating the control chamber with the pressure chamber, an orifice in the control chamber to permit pressure fluid to escape constantly from the control chamber to the atmosphere, a reset chamber in constant communication withthe control chamber, a valve for controlling the rate of flow of pressure fluid through the control chamber to vary the pressure therein, and a member for actuating said valve in response to variations in pressure in the reset chamber and acting responsively to such changes in pressure to maintain a constant pressure differential between the reset chamber and the control chamber whenever the pressure in the pressure chamber deviates from a predetermined value.

8. A regulator having separate pressure, control and reset chambers, an inlet constantly communicating the pressure chamber with. a source of pressure fluid, a passage for communicating the control chamber with the reset chamber, means for permitting pressure fluid to escape from the control chamber, a valve for controlling the flow of pressurefluid into the control chamber, and means responsive to variations in pressure differential between the reset chamber and the pressure chamberfor actuating said valve and acting in response to changes in'pressure in the reset chamber to maintain a constant pres sure differential between the reset and control chamber by varying the rate of flow of pressure fluid into the control chamber whenever the pressure in the pressure chamber deviates from a predetermined value and acting responsively to variations in pressure in the pressure chamber to vary in inverse proportion the' pressure in the control chamber by varying the rate of flow of pressure fluid into the control chamber.

9. A regulator having separate control, reset and pressure chambers therein, an inlet for constantly communicating the pressure chamber with the source of fluid under pressure, a passage communicating the control chamber with the reset chamber, a pressure fluid inlet and an outlet for the control chamber, a valve for controlling the rate of flow of pressure fluid through said inlet and outlet of the control chamber to vary the pressure therein, and a member having pressure surfaces exposed to pressure fluid in the pressure chamber and reset chamber and actuated in response to variations in pressure differential between the last two said chambers for actuating said valve.

10. 'A fluid actuated regulator having a pressure chamber in constant communication with a source of fluid under pressure, a'control chamber having a pressure fluid inlet and an outlet for the escape of pressure fluid from the control chamber, a valve for controlling the rate of flow of pressure fluid through the control chamber for varying the pressure therein, a reset chamber in constant communication with said control chamber, and means acting in response to variations in pressure in the reset chamber to vary the rate of flow through the control chamber whenever a pressure differential exists between the reset and control chamber.

11. A regulator having a pressure chamber in communication with a source of fluid the pressure of which is to be controlled, a control chamber in communication with a means actuated by variations in pressure in the control chamber to control the device to be regulated, a passage communicating the control chamber with the pressure chamber, an outlet for the control chamber, valve means for controlling the flow of REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 20,092 Mason Sept. 1, 1936 971,207 Michel Sept. 27, 1910 2,016,824 Smith Oct. 8, 1935 2,098,914 Gorrie Nov. 9, 1937 2,125,081 Moore July 26, 1938 2,285,540 Stein June 9, 1942 2,432,705 Williams Dec. 16, 1947 

